Chusetts



Dec. 28 1926.

N. G. LARSON ET AL LOAD LIFTING JACK Filed Oct. 23, 1925 (In :Y

IN V EN TOR.

, ATTORNEYS,

Patented Dec; 28, 1926.

'UNIVTED STAT-Es 1,612,447 PATENT OFFICE(- mLs LansoN AND rmx Mossnnne, or ATTLEnono, mssacnUsETTs, .assteivons To so-Lo-Jacx oo. mc., or BosToN, MASSACHUSETTS, A CORPORATION or mssa- CHUSETTS.

vLoan-Linnea nox.

I Application led ctober 23, 1925. Serial No. 64,834.

This invention relates to an improved construction of lifting jack which simulates the so-called lazy tongsr in itsaction the same being more particularly adapted to be positioned beneath the axles of an` automobile to lift the same; and the object of this invention is to provide a jack of this character which is adapted to 'be reduced very low in height so thatit may be positioned under the axle of the vehicle when the tires are deflated even tires of the so-called balloon type, which permit the axle to drop quite closely to the ground.

A further object of this invent-ion is to provide an improved construction of this lazy tongs type of jack wherein the lifting leverage is increased over the old style of lazy tongs type of jack particularly when in collapsed or lowered position.

The invention further consists in the provision of a set of arms on the jack which are pivotally connected together to simulate the lazy tongs action and to connect the power-ap lying screw to the arms at 'a point removed frrom the point where the arms are pivotally connected to each other thereby materially increasing the lifting leverage when the jack is in its lowered position.,

With these and other objects in view, the invention consists of certain novel features of construction, as will be more fully described, and particularly pointed out in the ap ended claims.

n the accompanying drawings: Figure 1 is a side .elevation of our improved construction of jack partly in section and in collapsedor lowered position.

Figure 2 1s a to "view of the device in' collapsed position s owing a portion of the load rest broken away.

Figure 3 is an end view ofthe jack in position shown in Figure 1.

Figure 4 is a side elevation illustratingA the jack in maximum raised position with portions of the load rest broken away.

It has been found in the old type of jack of the lazy tongs construction thatwhen the power is applied to the jack at the point where-the arms are pivoted together when in collapsed or lowered position that an excessive amount of power is required to lift the load; and to obviate this diiculty, I have connected the ower-applying screw to the arms of the device at a point removed from that point where the upper and lower` arms are pivoted together thereby materially increasing the leverage, and therefore, the lifting power of the jack particularly when in its collapsed position; and the following is a detailed description of the resent embodiment of my invention and s owingone means by which these advantageous results may be accomplished Withl reference to the drawings, l0 designates two pairs of upper arms of'the set, each pair being spaced from each other and both pairs being pivotally connected at onol end 11 to the load-rest 12, these ends of each pair of the set being provided with inter-l engaging teeth 13 which cause them to op' erate in unison. A The lower set of -arms 14:v also comprises two spaced airs which arc pivoted at one end 15 to `t e base 16 anfl these-arms of this set are also provided with intermeshing teeth 17 to cause them to move in unison.

The ends of these upper and lower sets of arms are pivoted together at the points 18 and above thesepoints in the space between the pairs of each set a pair of nuts or threaded members 19 are pivoted by'the pins 2() to the lower set of arms 14, at a point a substantial distance above the points 18 where the upper and lower sets of arms are pivoted together, and a power applying screw 21 is positioned in the space between these arms and is threaded into both of these nuts 19 and this screw is squared as at its end 22 to receive the usual operating wrench (not show-n).

It is found in practice that where the' power is applied at the point where the upper and lower arms are connected together thatwhen the jack is collapsed or droppedA to its lowest position that the power screw is in a disadvantageous position for exerting a lifting actionon the load but by moving the power exerting point 1to one side either above or below the pivoting point 18 of the -upper and lower arms to theextent illustrated in Figure 1, the lifting power is increased about three-fold and the further it is removed the greater the .lifting leverage exerted when the jack is in this collapsed position. The lifting power of lthe jack of course, graduallyincreases as it is raised and the angle between the arms is reduced. In other words, the further removed the point of power application is from the point where the arms are pivotedtogethel Cil the iower the jacir` may dropped and-stiil exert sucient newer to easily lift the load.

My improved jack is very simple and practical in construction and is eective in its action and by its use a heavy load may'1 be easily lifted even when the jack is lowered to its minimum height.

The foregoin description is directed solely towards t e construction illustrated, but we desire it to be understood that we reserve theprivilege of resorting to all the mechanical changes to which the device is susceptible, the invention being defined and limited only by the terms of the appended claims.

We claim:

1. A load-lifting jack comprising a base, a set of arms pivoted to sald base at one end, a load rest, a set of arms pivoted at one end to said -load rest and pivoted at their opposite ends to vthe first said set of arms, one of said sets of arms carrying portions oiset from a line between its pivotal end connections, and means for applying ower to said oiiset portions to move said cad-rest away from said base.

2.. A load-lifting jack comprising a base, a-set of arms l'pivoted to said base at one end, a load rest, a set of arms pivotedat one end to said load rest and pivoted at their opposite'ends to the rst said set of arms, one of said sets of arms carrying portions odset a iine between its pivotai lazy tongs action, the arms pivoted to one of l said members carrying portions oiset from a line between thedpivotal points between its ends, nuts pivote to said offset portions, and threaded means for applying ower to said nuts to relatively move said ase and load members. 4. A load-lifting jack comprising a base, a set of arms pivoted to said base at one end and having downwardly offset portions at their opposite ends, a load-rest, a set of arms pivoted to said rest at one end and pivoted to said offset portions at their opposite ends whereby said arms cross when the jack is in collapsed position, and means for applying power to said arms at a point above the pivotal connection joining said arms and between the pivotal connection of said arms. to said base and to said loadrest.

1n testimony whereof we affix our signatures.

NILS G. LARSON. FRANK MOSSBERG. 

